IPM Lawn Insect

Introduction

Several insects and related pests are common in lawns in Florida. Chinch bugs and spittlebugs suck plant juices. Mole crickets, white grubs, and billbugs live in the soil and damage the grass roots. Others including sod webworms, grass loopers, and armyworms, eat the grass leaves. To these groups can be added insects and related pests such as fleas, millipedes, chiggers, sowbugs, and snails that do not damage the lawn but may become nuisances because of their biting people or crawling into houses, garages, or swimming pools.

Beneficials

One group of insects often confused with these pests is actually beneficial. This group includes big-eyed bugs, anthocorids, and nabids that resemble chinch bugs but actually feed on chinch bugs' eggs and nymphs. The Labidura earwig, ground beetles, and spiders search through the grass and feed on chinch bugs, webworms, and several other lawn pests. The presence of these beneficial organisms will often prevent the insect pests from reaching damaging levels. It is necessary that a small population of pests be present to maintain these beneficial organisms. Preventative or scheduled treatments (pesticide applications every four to eight weeks) will reduce these beneficial organisms and may actually contribute to a persistent chinch bug, sod webworm or other pest problem. Apply pesticides only when damage is beginning to occur.

Monitoring

Inspect the lawn weekly during the spring, summer and fall months and biweekly during the winter months, as outlined in the sections of this publication relating to the various pests to determine if damage is beginning to occur and if insects are the problem.

Cultural Practices

Studies throughout Florida the past several years have demonstrated that the need for pesticide applications to control chinch bugs, sod webworms, and armyworms can be drastically reduced by following certain management practices.

Cultural practices can influence the susceptibility of lawn grasses to insect pests. Attention to the following practices will aid in a reduction of pesticide use which can result in less contamination of the urban environment and preservation of beneficial organisms. Rapid succulent growth resulting from frequent or high applications of water soluble nitrogen fertilizers acts as an attractant and substantially increases the chances of chinch bug and sod webworm attack. Incidence of damage from these pests can be greatly reduced with applications of minimum amounts of slow release nitrogen fertilizers in combination with other macro and minor nutrients. Contact your local Cooperative Extension Service office for fertility recommendations and sources of slow release nitrogen fertilizer for each of the turfgrass species in your particular area of the state.

Improper mowing and excessive water or fertilization can cause lawn grasses to develop a thick, spongy mat of dead and living shoots, stems, and roots that builds up between the layer of green vegetation and the soil surface. This spongy mat, referred to as thatch, is an excellent habitat for chinch bugs and turf caterpillars, and chemically ties up insecticides, therefore reducing their effectiveness. When a serious thatch problem exists, it may be necessary to remove the thatch mechanically (vertical mowing, power raking, etc.).

Proper mowing practices can make the grass more tolerant to pests and greatly improve the appearance of a lawn. St. Augustine should be mowed at a height of 3 to 4 inches, Centipede at 2 inches and Bahia at 3 to 4 inches. It is very important to keep the mower blade sharpened. The best recommendation is to mow often enough so that no more than one-third of the leaf blade is removed at each mowing. Do not remove the clippings.

Insects are only a few of the many causes of yellowish or brownish areas in grass. Diseases, nematodes, dry weather, and nutritional disorders are sometimes responsible for such injury. It is important to be sure of the cause so proper treatment can be applied to correct the trouble without needless use of pesticides and extensive damage to the grass.

An effective way to survey for chinch bugs, lawn caterpillars, mole crickets and beneficial insects is by the use of a soap mixture applied with a 2 gallon sprinkling can. This mixture is not effective in surveying for white grub or billbug larvae. Mix 1 1/2 fl. oz. of dishwashing liquid in a 2-gallon sprinkling can full of water and drench four square feet with this solution. Observe the area for about two minutes. If the above pests are present, they will emerge to the grass surface and can be detected. If no insects are found in the first area checked, examine at least three or four places in suspected areas.

Notes on Control

If insecticides are required, apply them properly. Read and understand all directions on the container label regarding dosage rates, application information, and precautions. When a spray is applied for controlling lawn insects, it is important to apply the insecticide in a large amount of water. The jar attachment to a garden hose is the suggested lawn sprayer for use on lawns. The type that requires 15 to 20 gallons of water passing through the hose to empty the quart size jar is recommended. Put the amount of insecticide in the jar as directed on the label for 1,000 square feet. Fill the jar the rest of the way with water. Spray the contents over 1,000 square feet. To insure even coverage, spray back and forth across the measured area; then, turn at right angles and spray back and forth across the same area.

When spraying for control of soil insects (mole crickets, white grubs, and billbugs), the turf should be moist at the time of application. Immediately after spraying the insecticide, irrigate with about 1/2 to 3/4 inch water to leach the insecticide into the soil where the insects are feeding. For control of surface feeders (chinch bugs, lawn caterpillars, bermudagrass mites, grass scales, and spittlebugs) do not irrigate after application.

Granule formulations of the recommended insecticides may be substituted for sprays in controlling chinch bugs, webworms, mole crickets, white grubs, or billbugs. If applied for soil insects (mole crickets, white grubs, or billbugs) irrigate with about 1/2 inch of water immediately after applying.

To help avoid unnecessary environmental contamination and reduction of beneficial insects, spot treatments for chinch bugs and webworms can be applied when infestations are first noticed and the damaged area is small. Treat the off-color area and about a 5 foot buffer area surrounding it. If damage is widespread over the yard or if many infested areas are detected, the entire yard should be treated. Inspect the area 2 to 3 times at bi-weekly intervals to determine if the infestation is under control.

If a bait is used for mole crickets, irrigate before application but do not irrigate after applying the bait. Apply late in the afternoon if possible. It is very important to scatter the bait thinly and evenly over the soil surface. A few particles should fall on every square inch of the infested area.

Precautions

Insecticides are poisons and should be handled as such. Read the manufacturer's label carefully before opening the container and observe all instructions and precautions. Wear rubber gloves when handling and applying insecticides. Do not spill sprays on skin or clothing. Do not breathe mists or fumes. Wash exposed parts of the body with soap and water immediately after using insecticides. Store pesticides under lock in original labeled containers out of reach of children. Rinse empty containers and put rinsings in spray tank. Dispose of empty containers (one gallon or smaller) by wrapping in newspaper, crush or puncture to prevent re-use, and put in garbage can for disposal in an approved sanitary land fill.

Additional Resources

University of Florida Mole Cricket Knowledgebase

 

Authors: C. W. Scherer, P. G. Koehler and D. E. Short - University of Florida

Photographs: University of Florida

Published: February, 1998